We study a possible physical realization of a quantum controlled-NOT gate with the use of two weakly coupled asymmetric quantum dots. Solving the time-dependent Schrödinger equation for the model two-electron sys...
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We study a possible physical realization of a quantum controlled-NOT gate with the use of two weakly coupled asymmetric quantum dots. Solving the time-dependent Schrödinger equation for the model two-electron system, we simulate the infrared-radiation-induced quantum transitions that correspond to basic gate operations. We require the transition probabilities to be close to 1 and optimize the parameters of the nanostructure in order to make the gate operation time as short as possible. In the simulations, we have taken into account the entire energy spectrum, which can be populated by the absorption or emission of the infrared radiation. We discuss the consequences of the existence of many bound two-electron states on the probability of radiative transitions.
New experimental data are presented on the gel electrophoresis of DNA. Experiment was made for molecules of length 173 kbp, in 1 percent agarose gel, in TAB 1x buffer and the field intensity between 5 and 9V/cm. The r...
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New experimental data are presented on the gel electrophoresis of DNA. Experiment was made for molecules of length 173 kbp, in 1 percent agarose gel, in TAB 1x buffer and the field intensity between 5 and 9V/cm. The results are compared with our computer simulations, performed within the repton model of Duke and Rubinstein. The ranges of field and molecule length are determined, where the geometration effect appears. We investigate also the field dependence of the velocity and the diffusion coefficient at the border of the geometration regime.
Thin films of polystyrene (PS)/ poly(methyl methacrylate) (PMMA) blends (50/50, w/w, binary composition) with PS- PMMA diblock copolymers added (weight fraction f{cyrillic}c = 0-0.10) have been spin cast on gold from ...
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Thin films of polystyrene (PS)/ poly(methyl methacrylate) (PMMA) blends (50/50, w/w, binary composition) with PS- PMMA diblock copolymers added (weight fraction f{cyrillic}c = 0-0.10) have been spin cast on gold from toluene solutions and examined with atomic and lateral force microscopy combined with selective dissolution. All films consist of PMMA lamella, adjacent to substrate, and lateral phase arrangement, facing surface and characterised by length scale R. Three types of film structure were observed: Por f{cyrillic}c = 0, surface undulations developed into isolated PMMA protrusions (2.5 ≤ R ≤5.1 μm) suggest interfacial (dewetting) instability of transient bilayer PS/PMMA, modified when diblocks segregate at interface. For f{cyrillic}c0.05, R is reduced to ~ 1 μm and micelle-like circular PMMA islands are formed. Por higher copolymer content, some of these islands become elongated and for f{cyrillic}c = 0.10 yield almost bicontinuous morphologies (with R - 2 μm) resembling emulsion.
Recently, a continuous dynamics was proposed to simulate dynamics of interpersonal relations in a society represented by a fully connected graph. The final state of such a society was found to be identical with the so...
Recently, a continuous dynamics was proposed to simulate dynamics of interpersonal relations in a society represented by a fully connected graph. The final state of such a society was found to be identical with the so‐called Heider balance (HB), where the society is divided into two mutually hostile groups. In the continuous model, a polarization of opinions was found in HB. Here we demonstrate that the polarization occurs also in Barabási‐Albert networks, where the Heider balance is not necessarily present. In the second part of this work we demonstrate the results of our formalism, when applied to reference examples: the Southern women and the Zachary club.
In the paper the use of parallel computing in the structural optimization which requires a large amount of computational time is presented. The parallel computing techniques is combined with evolutionary algorithm met...
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The noise of a fast charge sensitive amplifier (CSA) with an input MOS transistor working in moderate inversion region is discussed. The MOS transistor operation in moderate inversion region becomes especially importa...
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The noise of a fast charge sensitive amplifier (CSA) with an input MOS transistor working in moderate inversion region is discussed. The MOS transistor operation in moderate inversion region becomes especially important in multichannel readout systems, where limited power dissipation is required. The ENC of a CSA followed by a fast shaper is usually dominated by the thermal noise of the input MOS transistor. We perform the noise minimization of such CSA, searching for an optimum input transistor width. The analyses are done using a simplified EKV model and are compared to HSPICE simulations with BSIM3v3 model. We consider several CMOS technology generations with minimum transistor gate length ranging from 0.13 mum to 0.8 mum. We study the sensitivity of ENC to the input transistor width and propose a simple formula to estimate the optimum transistor width, which is valid in a wide range of the input transistor current density
We investigate magnetic properties of a two-dimensional periodic structure with Ising spins and antiferromagnetic nearest-neighbor interaction. The structure is topologically equivalent to the Archimedean (3,122) latt...
We investigate magnetic properties of a two-dimensional periodic structure with Ising spins and antiferromagnetic nearest-neighbor interaction. The structure is topologically equivalent to the Archimedean (3,122) lattice. The ground state energy is degenerate. In some ground states, the spin structure is translationally invariant, with the same configuration in each unit cell. Numerical results are reported on specific heat and static magnetic susceptibility against temperature. Both quantities show maxima at temperature T>0. They reveal some sensitivity on the initial state in temperatures where the Edwards–Anderson order parameter is positive. For zero temperature and low frequency of the applied field, the magnetic losses are negligible. However, the magnetization curve displays some erratic behavior due to the metastable states.
Transmultiplexing as a method of multiple-access in 4G-system is suggested in this paper. Every existing linear method of multiple-access can be treated as a specific transmultiplexer. Moreover, transmultiplexing real...
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Transmultiplexing as a method of multiple-access in 4G-system is suggested in this paper. Every existing linear method of multiple-access can be treated as a specific transmultiplexer. Moreover, transmultiplexing realizes the idea of intelligent network and reprogrammable electronic devices. The presented method uses perfect reversible integer-to-integer filter banks which have been attracting growing interest. Signals are then invertible in finite-precision arithmetics and map integers to integers. Due to this property, transmultiplexers of this type have important advantages: they can be applied for transmitting lossless compressed signals, minimal memory is needed and complexity of computations can be low.
An electron wave packet formed in a semiconductor heterostructure containing a quantum well covered by a metal surface is considered. It is demonstrated that the potential of the charge induced by the electron wave pa...
An electron wave packet formed in a semiconductor heterostructure containing a quantum well covered by a metal surface is considered. It is demonstrated that the potential of the charge induced by the electron wave packet on the conducting surface possesses a component of lateral confinement stabilizing its shape. The existence of electron solitons, i.e., running electron wave packets propagating without changing their shape, is demonstrated. In the scattering phenomena, the electron interacting with the induced charge tends to behave like a classical particle with the backscattering probability approaching a step dependence on the incident momentum as the distance from the metal surface is decreased. This effect enhances the ballistic character of transport for fast electrons and facilitates the trapping of slowly moving electrons.
E-tutorial systems recently played important roles in the teaching and learning of both online and conventional courses. Students have opportunities to study and practice exercises under guidance of the systems. A cha...
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E-tutorial systems recently played important roles in the teaching and learning of both online and conventional courses. Students have opportunities to study and practice exercises under guidance of the systems. A challenge in the development of e-tutorial systems is the design and implementation of the student guidance system. The guidance system should take into consideration the ability of individual students and give appropriate questions according to the student's ability. The students should finally reach the solution and gain better understanding of the learning topic. This paper presents the student guidance system of ESBO, a knowledge-based physics e-tutorial system. This system considers individual student's ability in a different approach from other existing systems.
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